FR2588861A1 - PROCESS FOR THE PREPARATION OF PARA-QUINONES - Google Patents

Abstract

THE INVENTION RELATES TO ORGANIC CHEMISTRY. IT CONSISTS OF A PROCESS FOR SYNTHESIS OF PARA-QUINONES I: (CF DRAWING IN BOPI) AND OF DERIVATIVES THEREOF BY REACTION OF APPROPRIATE AROMATIC COMPOUNDS WITH AN ACTIVE DICARBOXYL ACID (IN PARTICULAR DICHLORIDE) IN THE PRESENCE OF A METALLIC HALOGUE , IN RELATIVELY MILD CONDITIONS. THE COMPOUNDS OBTAINED ARE USEFUL INTERMEDIARIES FOR THE CHEMICAL AND PHARMACEUTICAL INDUSTRY.

Description

Process for the preparation of para-quinones

  The invention relates to a method for the preparation

  para-quinone and related compounds of the general formula:

R

R

R5 R3

GOLD(

O R4

  wherein A represents an aromatic or hetero ring

  5- to 6-membered aromatic, while R1, R2, R3, R4 or R5, which may be similar to each other or different,

  represent hydrogen, alkyl, aryl, hydro-

  xyl, alkoxy or a nitro group, furthermore, R1 + R2, or R2 + R3, or R3 + R4, may form another system

  cyclic, partially or totally unsaturated, ortho-

  condensed on the benzene nucleus, starting from hydroquinones

  or other aromatic compounds and dicarboxylic acids

  activated, preferably in the form of dichlorides.

  In particular, the invention relates to the preparation

  a single stage and wide applicability of 9,10-anthraquinones and similar compounds

  appropriate hydroquinones (or other aromatic substrates)

  with at least the free positions 2, 3 on

2-88861

  dicarboxylic acid dichlorides in the presence of a metal halide catalyst, in

solvents of medium polarity.

  The para-quinones thus prepared find varied and interesting applications. The most use

  of anthraquinone is the training of

  for the preparation of coloring pigments, see Kirk-Othmer Encyclopedia of Chemical Technology, volume

  8, pages 212-279 - John Wiley and Sons, New York 1979.

  Anthraquinone also finds use in the isomerization process of vegetable oils (V. Sarzf,

  Indian J. Appl. Chem. 22, 146 (1909) and as an accelerator

  in electrochemical processes (S. Katz,

  GB-A-1,029,686 (General Motors Corp.).

  Alkylanthraquinones are used in the manufacturing cycle of hydrogen peroxide (W.S. Schumb, Hydrogen Peroxide, ACS monograph n 128, Reinhold

Publishing Corp., 1955, page 77).

  Aminoanthraquinones find use in the synthesis of coloring pigments and act as stabilizers of photodegradable polystyrene resins (K. Nakamura, Kobunshi, Ronbushu 31 373 (1974); Chem. Abstr.,

81, 1365804 (1974)).

  Hydroxyanthraquinones are widely used

  sands in the preparation of coloring pigments and as antioxidants for lubricating oils (F. Oberender,

  DE-B-2 230 754 (January 25, 1973) (Texaco Development Corp.)).

  A very special class of anthraqui

  hydroxylated nones is constituted by 1,4-dihydroxy-

  9,10-variously substituted anthraquinones which represent

  the basic structure of antitumor anthracyclines

  (F. Arcamone, Doxorubicin Anticancer Antibiotics, Medici-

  Chemistry, Academic Press, 1981; S. Penco, The Chimica

  Industria, Vol. 65, No. 5, 359 (1983)).

  The methods used hitherto in the synthesis of 9,10-anthraquinone are based on four basic routes. The first consists of the oxidation of anthracene by various oxidizing agents such as

  dichromates, nitric acid, chlorine, molecular oxygen

  and Ozone (T. James, US-A-2,865,933 (Koppers, Co.), L. Mahoney, US-A-3,458,538 (Ford Motor Co.), L. Hutchings, US-A- 3,510,498 (Great Lakes Carbon Corp.), Calderazzo, US-A-3,642,838 (American Cyanamid Co.), H. Yasui JP-A-75,108,254 (Nippon Steel Chemical Co.), IT-A- 869,293

(A.C.N.A. S.p.a.)).

  The second method is based on the acylation of benzene with phthalic anhydride in the presence of aluminum chloride to give ortho-benzoylbenzoic acid which is cyclized in a second stage, in an acid medium. protic such as concentrated sulfuric acid, polyphosphoric acid or hydrofluoric acid (H. Stone, US-A-1,656,575 (E.C.

Klipstein and Sons Co.)).

  It is also possible to synthesize anthraquinone by reaction of DielsAlder between 1,4-naphthoquinone and 1,3-butadiene at 100-110 ° C. in an autoclave, followed by oxidation in the air of tetrahydroanthraquinone. so

  obtained (K. Sakuma, DE-A-2,460,922 (Nippon Stec Chemical Co.)).

  A new preparation of 9,10-anthraquinone has recently been reported and is based on the oxidation of indane obtained by dimerization of styrene (H. Armbrust, US-A-3,764,631 (Badische Anilin und Soda Fabrik); H. Armbrust

  US-A-3,714,240 (Badische Anilin und Soda Fabrik); H. Engel-

bach, DE-A-2 314 695 (BASF)).

  Synthesis via phthalic anhydride

  can also be used in the preparation of 2-alkyl-

  anthraquinones, but the severe operating conditions

  (high temperature and extremely acidic environments)

  There is little control over the reaction sites and isomerizations when using aromatic compounds bearing long chains of carbon atoms (C.A. Thomas, Anhydrous Aluminum Chloride in Organic Chemistry, Monograph A.C.S. No. 87, Reinhold

Publishing Corp., New York 1941.

  Methylanthraqui-

  from 1,4-naphthoquinones and methylbutadiene according to the Diels-Alder reaction (H. Koehl,

DE-B-2 162 949 (BASF).

  Various hydroxyanthraquinones are prepared according to the phthalic route and according to the Diels-Alder reaction (F. Arcamone, Doxorubicin Anticancer Antibiotics, Medicinal Chemistry, Academic Press, 1981, S. Penco, La Chemica e

Industria, 65, 359 (1983)).

  It should be noted, however, that the above processes suffer from significant limitations, especially because the generally severe reaction conditions preclude the possibility of obtaining, with economically acceptable yields, paraquinones bearing substituent groups which under the conditions reactions, undergo isomerizations or racemisations, when it does not occur purely and simply

  severe degradation of end products.

  The object of the invention is therefore to provide a

  process for the preparation of para-quinones and

  related products which is widely applicable, direct and relatively simple and gentle, characterized by good yields, high selectivities, control on reactive sites and stereochemistry and finally, using catalysts and solvents economical and easy to

find on the market.

  These goals, as well as others that will appear

  more obvious to the skilled person through the description

  following, are achieved according to the present invention by

  to a process for the synthesis of para-quinones I characterized

  in that activated dicarboxylic acids are reacted, preferably in the form of acyl II COC1 dichlorides.

A (II)

  COCl R5 o A and R5 have the meanings specified above, on an aromatic substrate of general formula III R1

R 2

0 | (III)

R

1 3

  R o R1, R2, R3, R4 have the meanings already specified,

  in a virtually stoichiometric ratio, at

  between 80 and 120 ° C., preferably at about 100 ° C., in the presence of a metal halide to be chosen from Group III or IV metal halides.

  of the Periodic Classification or of transition metals

  preferably aluminum chloride or bromide

  anhydrous at a level of 2 to 3 molar equivalents

  to the aromatic compound III in a medium

  such as nitrobenzene, nitromethane and

tetrachlorethylene.

  The concentrations of species III in the solvent are not critical and can vary between 5 and 30% by weight approximately. Thus, according to the present process, the direct selective synthesis of para-quinoneS is obtained by going through an (apparent) bis-acylation of two adjacent carbon atoms of the aromatic nucleus, while minimizing the

oxygen attack products.

  Solvents which have appeared to be effective are the aprotic polar compounds such as nitro derivatives (nitrobenzene, nitromethane),

  polyhalogenated hydrocarbons (tetrachlorethylene).

  The reaction times are variable depending on the operating temperatures and the reactivity of the substrates chosen; in practice, at 1000C, times of 10

  minutes to 1 hour are sufficient to bring the process

  on completion. Stirring of the reaction mass is advantageous for greater efficiency. It must also be emphasized that the operating conditions of the whole process are particularly mild and that

  the reaction takes place with total maintenance of

  when using optically active reagents.

  According to a particular mode of implementation-

  In a preferred embodiment, the process according to the present invention is carried out by first dissolving the Lewis acid (at a rate of about 2 to 3 moles per mole of aromatic substrate III) in the solvent, adding the substrate III to the solution. , optionally also dissolved in the same solvent and heating all to a temperature of the order of 100 C. After about 5 minutes of stirring at this temperature, the dichloride II, dissolved in the same solvent, and at such a rate that the temperature is maintained near 100 C without further external heating. Once the addition is complete, the mixture is still stirred at the same temperature for about thirty minutes, the mass is allowed to cool to room temperature and quenched with an excess of saturated aqueous solution of oxalic acid. The mixture is extracted several times with diethyl ether and the extracts are dried.

pooled on anhydrous Na 2 SO 4.

  Evaporation of the solvent under reduced pressure provides the crude product which is separated from the compounds of

  initially not consumed, by crystallisation in soil

  or by chromatography on silica.

  Reference has already been made to the fact that

  are not critical. In the preferred process described above, the concentration of the initial solution of the Lewis acid (eg AlCl 3) in the solvent (eg nitrobenzene) can vary from 5 to 20% w / v; those of aromatic substrate III and dichloride II may vary between 10 and 30% w / v. As already mentioned, training

  anthraquinone starting from ortho-benzoyl

  benzoic acid occurs only under severe conditions, by the intervention of highly protonating agents. of the

  kinetic studies on the behavior of ortho-

  Benzoylbenzoic agents in the presence of such agents have led to the formulation of a mechanism which can be summarized as follows:

0 OH

+ HA

CXYH

  + DO o HA is hydrofluoric, polyphosphoric or sulfuric acid: see M.S. Newman et al., J. Am. Chem. Soc. 67, 704 (1945); R. J. Downing et al., Ibido 84, 4956 (1962); D. S. Noyce et al., J. Org. Chem., 30,

1896 (1965).

  The surprising aspect of the invention is constituted, as already mentioned, by the particularly mild reaction conditions, with all the advantages of regiospecificity and persistence of the chirality which result from it, advantages unknown when operating according to known techniques for obtaining anthraquinones and analogues. The interpretation that can be given of the reaction claimed here, on the basis of the results

  experimental, is that which provides for the formation of in-

reactive intermediates IV:

X Y

A0 O (IV)

  R (oA and R5 have the meanings specified above, while X is a halogen, an alkoxy or aryloxy group and Y is a halogen, an alkoxy or aryl group), which

  come from a) the transposition of mono-

  acylation, analogous to that assumed in Scheme 1, or b) of the reaction of dichlorophthalides or dialkoxyphthalides of formula V z Z '

A (V)

O

  (o A and R5 have the meanings specified above, while Z and Z ', similar to each other, represent

  chlorine or an alkoxy group) on aromatic substrates.

  III. Reactions a) and b) can be illustrated

  in Figure 2, which uses as examples two

  Suitable starting materials are phthalic acid dichloride (or corresponding dichlorophthalide, see A. Kirpel et al., Ber., 68, 1330 (1935)) and 1,4-dimethoxybenzene. Scheme 2 COCi a) C I x CoC 'OCH Aid3 AIC13 OCH AlC13 N

C1 C1

coci b) XAidl3 Coci OCH3 OCH 3

O OCH

  (VI) AiCl3 D-- (VI) AtC1 3-4 H It appeared that intermediate VI could not be isolated, but scheme 2 is supported by the fact that, if the reaction between the dichloride is carried out phthalic acid and 1,4-dimethoxybenzene - the other conditions being unchanged - at low temperature (25 ° C.) and for short periods (5 minutes), anthraquinone products are not obtained, but isolated two compounds to which structures VII and VIII have been assigned: CH I3 OCH

3 H CO

OICH; H 3 ^ 4 At} OCH3 H CO OCH3 o

(VII) (VIII)

  The formation of the compound VII [1- (4-methoxyphenoxy) -

  1- (2,5-dimethoxyphenyl) -isobenzofuran-3] can be attributed to the attack of chlorophthalide VI on oxygen

  a methoxy group; that of compound VIII [1,1-bis- (2,5-

  dimethoxyphenyl) -isobenzofuran-3] to attack the same

  chlorophthalide on a cyclic carbon atom of

  thoxybenzène. Now, by heating VII under the conditions

  of the present process, 1,4-dihydroxy-9,10-

  anthraquinone with a quantitative yield, through an intramolecular acylation favored by the breakage of a C-O bond and thus by the detachment of a good leaving group (p-methoxyphenol); in the case of VIII, there should be a break in an energy-poor C-C bond: and in reality,

  VIII does not appear convertible into 1,4-dihydroxy-9,10

anthraquinone.

  The invention therefore comprises a process for the preparation of para-quinones I starting from isolated intermediates of type IV and V; and the invention also includes intermediates of this type when they are

new.

  The invention will now be described more precisely

  in the following examples, given for illustrative purposes only. The table shows the structures of the products synthesized in the various

examples.

  TABLE: Structure of the products obtained in the various examples.

Example 1

  To 26.6 g (0.2 mol) of anhydrous AlCl.sub.3 in 300 ml of nitrobenzene is added, at room temperature and under a gentle flow of dry nitrogen, 7.2 g (0.2 mol) of benzene. . It is heated to 100 ° C .; After stirring for 15 minutes at this temperature, 20.2 g (0.1 mol) of phthalic acid dichloride dissolved in 100 ml of nitrobenzene are added over a period of about 20 minutes. We

  bring the volume of the solution to 500 ml with nitrobenzene

  zen and the temperature is maintained at 100 ° C. under stirring.

  The reaction mixture is cooled for 30 minutes and then the reaction mass is cooled and 300 ml of saturated aqueous oxalic acid solution are added under intense stirring. 200 ml of ethyl ether are extracted three times with each other and the combined extracts are dried over anhydrous Na 2 SO 4. The solvent is removed under reduced pressure and the product is purified by crystallization from toluene. 17.7 g (85% yield) of 9,10-anthraquinone (1) are obtained.

  mp 285 C (literature 286 C, C2H5OH).

Example 2

  According to the same procedures as in Example 1, but using 11.0 g (0.1 mole) of hydroquinone and 1 g (0.1 mole) of phthalic acid dichloride,

  obtains 15.6 g (65% yield) of 1,4-dihydroxy-9,10-

  anthraquinone (2), melting point 199 C (literature

-202 C, C2H5OH).

ExempLe 3

  In the same way as in Example 1,

  but using 12.4 g (0.1 mole) of 2-methylhydroquinone

  and 20.2 g (0.1 mole) of phthalic acid dichloride.

  15.7 g (62% yield) of 2-methyl-

  1,4-dihydroxy-9,10-anthraquinone (3), melting point

  177-178 ° C (literature 178-179 ° C, C2H5OH).

Example 4

  Following the same procedures as in the example

  ple 1, but using 11.0 g (0.1 mol) of hydroquinone

  and 20.3 g (0.1 mole) of the 3,4-pyridine acid dichloride

  dicarboxylic acid, 14.5 g (60% yield) of 6-aza-1,4-dihydroxy9,10-anthraquinone (4), mp 174-176 ° C (C 2 H 5 OH) are obtained. The compound was characterized as follows: IR (KBr, cm-1):

  2918, 1722, 1618, 1441, 1259, 1211, 792, 761.

  1H NMR (CDCl3, δ): 7.38 (s, 2H, H-2 and H-3); 8.12 (d, 1H, H-8, J = 5.0 Hz); 9.13 (d, 1H, H-7, J = 5.0 Hz); 9.62 (s, 1H, H-5); 12.66

(s, 1H, OH); 12.79 (s, 1H, OH).

  Mass spectrum (m / e, relative intensities%):

  241 (100), 213 (10), 185 (9), 171 (9), 102 (12).

UV (C2H5OH):

  To 206 230 259 (s) 296 463 (fl) 488 522 (s)

  E 14580 17951 7749 5440 4065 4421 3174.

ExempLe 5

  By a method analogous to that of Example 1, but using 11.0 g (0.1 mole) of hydroquinone and

  24.7 g (0.1 mole) of the dichloride of 4-nitrophthalic acid

  21.4 g (75% yield) of 6-nitro-1,4-

  9,10-dihydroxy-anthraquinone (5), mp 226-

  228 C (C2H5OH). The compound was characterized as follows: IR (KBr, cm-1):

  1625, 1598, 1528, 1440, 1330, 1238, 1205, 1145, 790, 762.

  1H NMR (CDCl3, d): 7.42 (s, 2H, H-2 and H-3); 8.5-8.7 (m, 2H, H-7 and H8); 9.16 (d, 1H, H-5, J = 1.7 Hz); 12.75 (s, 1H, OH); 12.78

(s, 1H, OH).

  Mass spectrum (m / e, relative intensities%):

  285 (100), 255 (10), 239 (27), 227 (10), 211 (28), 183

(24), 127 (26).

UV (C2H5OH):

  X 253 260 264 319 469 (fl) 495 530 (fl)

  e 18104 18638 17745 2686 6140 6782 4254.

Example 6

  By a method analogous to that of Example 1, but using 11.0 g (0.1 mole) of hydroquinone and

  19.2 g (0.1 mole) of 3,4-furan acid dichloride

  dicarboxylic acid, 1,4-dihydroxy-curano-naphthoquinone (6), mp 163-165 ° C., is obtained in a yield of 40%. The compound has been characterized as follows: IR (KBr, cm1):

  3094, 2900, 1665, 1600, 1515, 1274, 1120, 857, 840.

  1 F NMR (CDCl3, δ): 7.28 (s, 2H, H-5 and H-7); 8.25 (s, 2H, H-2 and H-3); 12.79

(s, 2H, OH).

  Mass spectrum (m / e, relative intensities%):

  230 (100), 184 (10), 147 (55), 122 (80), 107 (75).

UV (C H 5 OH):

  206,223,285 438,448,455 (s) 477 (s)

  e 7858 8638 1814 2401 2382 1922 1491.

Example 7

  According to the modalities of Example 1, but using 12.4 g (0.1 mole) of 2-methylhydroquinone and

  19.2 g (0.1 mole) of 1,4-furan acid dichloride

  dicarboxylic acid, there is obtained 10.2 g (yield 42%) of 2-methyl-1,4dihydroxy-c-furanonaphthoquinone (7), melting point 150-151 C. The compound was characterized as follows: -1 IR (KBr , cm):

  3100, 2910, 1670, 1609, 1522, 1283, 1222, 1130, 864, 848.

  1 H NMR (CDCl 3, 6): 2.34 (d, 3H, Ar-CH 3, J = 1.1 Hz); 7.54 (s, 2H, H-5 and H-7); 8.21 (d, 1H, H-3, J = 1.1 Hz); 12.81 (s, 1H, OH); 13.20 (s,

1H, OH).

  Mass Spectrum (m / e; relative intensities%):

  244 (50), 184 (10), 147 (100), 119 (38).

UV (C2H5OH):

  X 207 248 (s) 254 (fl) 440 448 468 (s) 478 (s)

  E 17492 7692 7571 2342 2428 1935 1500.

  EXAMPLE 8 By a method analogous to that of Example 1, using 11.0 g (0.1 mole) of 1,2-dihydroxybenzene and 20.2 g (0.1 mole) of phthalic acid dichloride ,

  13.2 g (55% yield) of 1,2-dihydroxy-9,10-

  anthraquinone (8), mp 288-289 C (literature

288-289 C, C2H5OH).

Example 9

  By a method analogous to that of Example 1, but using 16.4 g (0.1 mole) of 1,4-dihydroxy-5,6,8,8-tetrahydronaphthalene and 20.2 g (0.1 mole) of phthalic acid dichloride gives 33.7 g (yield 88%) of 6,11-dihydroxy-7,8,9,10-tetrahydro-5,12-naphtacenequinone

  (9), mp 194-1960 (Ce50OH).

ExempLe 10

  According to the method of Example 1, using 16.0 g (0.1 mole) of naphthohydroquinone and 20.2 g (0.1 mole) of phthalic acid dichloride, 15.9 g (yield 55%) of 6,11-dihydroxy-5,12-naphthacenequinone

  (10), mp 214-216 ° C (C2e501).

ExempLe 11

  By a process analogous to that of Example 1, using 12.8 g (0.1 mole) of naphthalene and 20.2 g (0.1 mole) of phthalic acid dichloride, 23.2 was obtained. g (85% yield) of benzo [a] anthracene-7,12dione

  (11), mp 168-170 ° C (literature 169 ° C).

ExempLe 12

  By a process analogous to that of Example 1,

  using 25.0 g (0.1 mole) of (-) - 7-acetyl-7-oxy-1,4-

  dimethoxytetrahydronaphthalene and 20.2 g (0.1 mol) of phthalic acid chloride, 29.9 g (85% yield) of (-) - 4-dimethoxy-7-deoxydaunomycinone (11), m.p. 210 C, [α] 20 = -19 (c = 0.09 g / 100 ml of [] D

C2H50H / CHCl3 1/1).

* Example 13

  By a process analogous to that of Example 1, using 10.8 g (0.1 mole) of anisole and 20.2 g (0.1 mole) of phthalic acid dichloride, 19, 0 g (60% yield) of 2-methoxy-9,10-anthraquinone (13),

melting point 195-197 C.

  Example 14 (isolation of intermediates) To the solution of 0.2 mol of AlCl 3 in 300 ml of nitrobenzene at room temperature, 0.1 is added

  mole of 1,4-dimethoxybNzane dissolved in 100 ml of nitro-

Eviron

  benzene and then, at / 20 C and rapidly, 0.1 mole of di-

  phthalic acid chloride. It is stirred for 5 minutes at 250 ° C., then a saturated aqueous solution of oxalic acid is added in one go. After the usual extractions with ethyl ether, an organic phase is obtained which is dried over Na 2 SO 4. The solvent is removed under vacuum; the residue is chromatographed on silica gel (eluent: hexane / ethyl acetate 1/1). Compounds VII and VIII are obtained with a respective yield of 40% and 30% relative to dimethoxybenzene. Compound VII (MW = 392)

  was subjected to mass spectroscopy with the results

  following states (m / e, relative intensities): 392 (15),

  269 (10), 255 (8), 165 (6), 137 (5), 123 (5). By treatment

  by A1C13 in nitrobenzene (100 C, 20 minutes),

  it is converted quantitatively into 1,4-dihydroxy-9,10-

anthraquinone (2).

  Compound VIII (MW = 406), proposed structure: H3CO

H H CO

  was characterized as follows: 1 H NMR (CDCl 3, d): 3.46 and 3.70 (12H, OCH 3); 6.85 (s, 4H, H-3 ', H-4', H-3 ", H-4"); 6.90 (s, 2H, H-6 'and H-6 "), 7.48 and 7.60 (2t, 2H, H-4 and H-5, J = 9.0 Hz); 88 (d, 2H, H-3 and H-6, J =

9.0 Hz).

  Mass spectrum (m / e, relative intensities%):

  406 (100), 375 (6), 347 (29), 331 (20), 269 (40), 239 (19,

211 (20).

Claims (8)

  1. Process for the preparation of para-quinones of the general formula R 0 1 R + oR 5 R eetoeuaremR 24 Cf f (II) O R4   wherein A represents an aromatic or hetero ring   5- to 6-membered aromatic, while R1, R2, R3, R4 or R5, which may be similar to each other or different,   represent hydrogen, alkyl, aryl, hydro-   xyl, alkoxy or a nitro group, furthermore, R1 + R2, or R2 + R3, or R3 + R4, may form another system   cyclic, partially or totally unsaturated, ortho-   condensed on the benzene ring, characterized in that aromatic substrates of formula III are reacted R1 R2 R (Iii) I 3 R 4   (wherein R 1, R 2, R 3 and R 4 have the meanings specified above) on reactive compounds selected from the group consisting of carboxylic acid dichlorides II and phthalides of formula IV ## STR1 ## (IV) (wherein A and R5 have the meanings specified above, while X is halogen, alkoxy or aryloxy and Y is halogen, alkoxy or aryl), in the presence of selected metal halides in the group consisting of Group III and IV metals   of the Periodic Table and the transition metals   in medium polar solvents.   2. Method according to claim 1, characterized in that the ratio between the aromatic substrates III   and the reactive compounds II (IV) is practically stable. stoichiometric.   3. Method according to one of claims 1 and 2,   characterized in that the metal halide is used in an amount of 2 to 3 moles per mole of aromatic substrate III.   4. Method according to one of claims 1 to 3,   characterized in that, as the halide   metal, AlCl3 or anhydrous AlBr3.   5. Method according to one of claims 1 to 4,   characterized in that a chosen solvent is used   between nitrobenzene, nitromethane and tetrachloro- ethylene.   6. Method according to one of claims 1 to 5,   characterized in that one operates at temperatures between 80 and 120 C.   7. Method according to one of claims 1 to 5,   characterized by the following steps: a) the metal halide is first dissolved in the solvent; b) the aromatic substrate III, optionally dissolved in the solvent, is added thereto; c) the solution obtained in b) is heated to approximately 100 ° C.; d) Gradually adding, at the same temperature, the reactive compound II (IV), optionally also dissolved in the solvent; e) at the end of the reaction, the mixture obtained is treated with an excess of saturated aqueous solution of oxalic acid and the reaction products are isolated by means of in themselves known.   8. A novel compound selected from the group consisting of: 6-aza-1,4-dihydroxy-9,10-anthraquinone; 6-nitro-1,4-dihydroxy-9,10-anthraquinone; 1,4-dihydroxy-c-furano-naphthoquinone; 2-methyl-1,4-dihydroxy-curanonaphthoquinone;   1- (4-methoxyphenoxy) -1- (2,5-dimethoxyphenyl) isobenzene zofurannone-3;   1,1-bis- (2,5-dimethylphenyl) isobenzofuran-3-one.